An Adaptive Element-Level Impedance-Matched ASIC With Improved Acoustic Reflectivity for Medical Ultrasound Imaging.

Area of Science:

• Ultrasound transducer technology
• Electrical engineering
• Acoustic imaging

Background:

• Ultrasound transducers require precise impedance matching for optimal performance.
• Minimizing acoustic reflections and crosstalk is crucial for high-resolution imaging.
• Existing impedance matching techniques have limitations in bandwidth and efficiency.

Purpose of the Study:

• To present an active impedance matching scheme for ultrasound transducers.
• To optimize electrical power transfer and minimize acoustic reflectivity.
• To improve bandwidth, uniformity, and reduce crosstalk in transducer arrays.

Main Methods:

• Development of a negative capacitance-based impedance matching scheme.
• Design of a 16-element transceiver front-end with element-level active capacitive impedance cancellation.
• Utilizing an element-level negative impedance converter and a 180-nm HVBCD fabricated ASIC.
• Integration with a 1-D capacitive micromachined ultrasonic transducer (CMUT) array.

Main Results:

• Demonstrated reduction in acoustical reflectivity.
• Successful acoustic imaging experiments and pulse-echo measurements.
• The ASIC supports high-voltage pulses (up to 60 V) with low power consumption (3.6 mW) and small area (2.5 mm²).

Conclusions:

• The active impedance matching scheme effectively enhances electrical power transfer and reduces acoustic reflectivity in ultrasound transducers.
• The developed front-end ASIC and CMUT array integration show significant improvements in imaging capabilities.
• This approach offers a promising solution for next-generation ultrasound imaging systems.